Exam Practice Questions And Correct

4th Class Stationary Engineer License Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a boiler?
• To store water
• To convert water into steam
• To cool steam
• To circulate feedwater

Rationale: Boilers heat water to produce steam for power, heating, or

process use.

• The device that prevents boiler pressure from exceeding safe limits is

the: 1 / 4

• Water column
• Steam gauge
• Safety valve
• Fusible plug

Rationale: The safety valve automatically releases pressure when limits are

reached.

3. The lowest safe operating water level in a boiler is known as the:

• Feedwater line
• Low-water cutoff
• Normal water level
• Overflow point

Rationale: The low-water cutoff prevents firing if water reaches unsafe low

levels.

• Which boiler mount is used to measure internal pressure?
• Water glass
• Pressure gauge
• Try cock
• Feed pump

Rationale: Pressure gauges display boiler pressure to operators.

• What is the primary function of a boiler economizer?
• Increase water circulation
• Recover residual heat from flue gases 2 / 4

• Add chemicals to feedwater
• Reduce fuel pressure

Rationale: Economizers preheat feedwater using waste heat to improve

efficiency.

6. The ASME code section for power boilers is:

• Section IV
• Section I
• Section VIII
• Section V

Rationale: ASME Section I governs construction of power boilers.

7. A steam trap’s purpose is to:

• Increase boiler blowdown
• Remove condensate without losing steam
• Vent excess air
• Reduce feedwater temperature

Rationale: Steam traps discharge condensate while retaining live steam.

• The boiler component that removes sludge and sediment from the

bottom is the:

• Surface blowdown
• Bottom blowdown
• Feedwater line
• Water column 3 / 4

Rationale: Bottom blowdown removes solids that settle at the lowest part

of the boiler.

9. Scale buildup in a boiler is caused by:

• Excessive airflow
• Hard water minerals
• Low flue gas temperature
• Softened feedwater

Rationale: Hard minerals form deposits that reduce heat transfer

efficiency.

10. A boiler's hydrostatic test is performed to check:

• Fuel quality
• Water hardness
• Pressure vessel integrity
• Combustion efficiency

Rationale: Hydrostatic tests confirm strength and leak tightness by

pressurizing with water.

11. A low-water condition in a boiler may cause:

• Scale removal
• Lower pressure
• Improved efficiency
• / 4